US8836689B2 - Display device - Google Patents

Display device Download PDF

Info

Publication number
US8836689B2
US8836689B2 US13/560,133 US201213560133A US8836689B2 US 8836689 B2 US8836689 B2 US 8836689B2 US 201213560133 A US201213560133 A US 201213560133A US 8836689 B2 US8836689 B2 US 8836689B2
Authority
US
United States
Prior art keywords
switch
driving transistor
electrically connected
capacitor
electrode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related, expires
Application number
US13/560,133
Other languages
English (en)
Other versions
US20130033475A1 (en
Inventor
Hiroyuki Miyake
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Semiconductor Energy Laboratory Co Ltd
Original Assignee
Semiconductor Energy Laboratory Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Semiconductor Energy Laboratory Co Ltd filed Critical Semiconductor Energy Laboratory Co Ltd
Assigned to SEMICONDUCTOR ENERGY LABORATORY CO., LTD. reassignment SEMICONDUCTOR ENERGY LABORATORY CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MIYAKE, HIROYUKI
Publication of US20130033475A1 publication Critical patent/US20130033475A1/en
Application granted granted Critical
Publication of US8836689B2 publication Critical patent/US8836689B2/en
Expired - Fee Related legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G5/00—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
    • G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
    • G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
    • G09G3/3208—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
    • G09G3/3225—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
    • G09G3/3233—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix with pixel circuitry controlling the current through the light-emitting element
    • G09G3/3241—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix with pixel circuitry controlling the current through the light-emitting element the current through the light-emitting element being set using a data current provided by the data driver, e.g. by using a two-transistor current mirror
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/0257—Doping during depositing
    • H01L21/02573—Conductivity type
    • H01L21/02576—N-type
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/0257—Doping during depositing
    • H01L21/02573—Conductivity type
    • H01L21/02579—P-type
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
    • H10D30/00—Field-effect transistors [FET]
    • H10D30/60—Insulated-gate field-effect transistors [IGFET]
    • H10D30/63—Vertical IGFETs
    • H10D30/635—Vertical IGFETs having no inversion channels, e.g. vertical accumulation channel FETs [ACCUFET] or normally-on vertical IGFETs
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2300/00—Aspects of the constitution of display devices
    • G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
    • G09G2300/0809—Several active elements per pixel in active matrix panels
    • G09G2300/0814—Several active elements per pixel in active matrix panels used for selection purposes, e.g. logical AND for partial update
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2300/00—Aspects of the constitution of display devices
    • G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
    • G09G2300/0809—Several active elements per pixel in active matrix panels
    • G09G2300/0819—Several active elements per pixel in active matrix panels used for counteracting undesired variations, e.g. feedback or autozeroing
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2300/00—Aspects of the constitution of display devices
    • G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
    • G09G2300/0809—Several active elements per pixel in active matrix panels
    • G09G2300/0842—Several active elements per pixel in active matrix panels forming a memory circuit, e.g. a dynamic memory with one capacitor

Definitions

  • the present invention relates to a display device.
  • the present invention relates to a display device including a light-emitting element which emits light utilizing electroluminescence.
  • a display device including a light-emitting element which emits light utilizing electroluminescence has been developed as an active matrix display device. Specifically, a display device has been developed in which the light-emitting element is provided in each of pixels arranged in matrix and desired display is performed by appropriately controlling a current which is supplied to each light-emitting element.
  • the light-emitting element include an element containing an organic material which emits light utilizing electroluminescence (also referred to as an organic EL element or an organic light-emitting diode).
  • a means to control the current which is supplied to each light-emitting element are needed.
  • a means to control a current which is supplied to a light-emitting element by using a transistor is known (e.g., see Patent Document 1).
  • the means are known in which a transistor whose source and drain are connected to a light-emitting element in series between a wiring for supplying a high power source potential VDD (also referred to as a high power supply potential line) and a wiring for supplying a low power supply potential VSS (also referred to as a low power supply potential line) is provided in each pixel.
  • VDD high power source potential
  • VSS also referred to as a low power supply potential line
  • a pixel illustrated in FIG. 3A includes an n-channel transistor 1001 A whose drain is electrically connected to a high power supply potential line, and a light-emitting element 1002 A whose anode is electrically connected to a source of the n-channel transistor 1001 A and whose cathode is electrically connected to a low power supply potential line.
  • a pixel illustrated in FIG. 3A includes an n-channel transistor 1001 A whose drain is electrically connected to a high power supply potential line, and a light-emitting element 1002 A whose anode is electrically connected to a source of the n-channel transistor 1001 A and whose cathode is electrically connected to a low power supply potential line.
  • a pixel illustrated in FIG. 3B includes a p-channel transistor 1001 B whose source is electrically connected to a high power supply potential line, and a light-emitting element 1002 E whose anode is electrically connected to a drain of the p-channel transistor 1001 B and whose cathode is electrically connected to a low power supply potential line.
  • a pixel illustrated in FIG. 3C includes an n-channel transistor 1001 C whose source is electrically connected to a low power supply potential line, and a light-emitting element 1002 C whose cathode is electrically connected to a drain of the n-channel transistor 1001 C and whose anode is electrically connected to a high power supply potential line.
  • 3D includes a p-channel transistor 1001 D whose drain is electrically connected to a low power supply potential line, and a light-emitting element 1002 D whose cathode is electrically connected to a source of the p-channel transistor 1001 D and whose anode is electrically connected to a high power supply potential line.
  • the pixel illustrated in FIG. 3B is most commonly used in consideration of the following two technical viewpoints.
  • the first viewpoint is a change in potential of a node where a driving transistor and a light-emitting element are electrically connected to each other, which is caused by deterioration of the light-emitting element over time or a change in environment temperature.
  • the potential of the source of the driving transistor is kept constant.
  • the voltage between the gate and the source of the driving transistor which is included in each of the pixels illustrated in FIGS. 3B and 3C can be kept irrespective of whether or not the light-emitting element deteriorates over time and the environment temperature is changed. Accordingly, in the pixels illustrated in FIGS.
  • a current which is supplied to the light-emitting element at the time when the driving transistor is operated in a saturation region can be kept substantially constant irrespective of whether or not the light-emitting element deteriorates over time and the environment temperature is changed.
  • the potential of the source of the driving transistor included in each of the pixels illustrated in FIGS. 3A and 3D is changed in response to deterioration of the light-emitting element over time or a change in environment temperature. In other words, a voltage between the gate and the source of the driving transistor included in each of the pixels illustrated in FIGS.
  • the current which is supplied to the light-emitting element is changed in response to the deterioration of the light-emitting element over time or the change in the environment temperature.
  • the second viewpoint is a manufacturing process.
  • Each of the light-emitting elements included in the pixels illustrated in FIGS. 3A to 3D emits light which is generated by electroluminescence between a pair of electrodes (the anode and the cathode) to the outside. Therefore, at least one of the pair of electrodes needs to transmit light.
  • a light-transmitting material such as indium tin oxide (also referred to as ITO).
  • ITO indium tin oxide
  • Such a material is preferably used for an anode because of its relatively high work function. Further, such a material is generally formed by a sputtering method.
  • the light-emitting element is an organic EL element
  • the organic material when the formation of the material is performed by a sputtering method after an organic material is formed, the organic material might be damaged. Therefore, in the manufacturing process of a driving circuit and a light emitting element, the following order is preferable: a driving transistor and an anode to be included in a light-emitting element are formed, and then an organic material to be included in the light-emitting element is formed.
  • the pixel configurations illustrated in FIGS. 3B and 3C are convenient from the first viewpoint, and the pixel configurations illustrated in FIGS. 3A and 3B are convenient from the second viewpoint. Accordingly, the use of the pixel configuration illustrated in FIG. 3B as the configuration of a pixel in a display device is convenient from the two viewpoints.
  • a problem to be solved in one embodiment of the present invention is the one which might occur in the pixels illustrated in FIGS. 3A and 3D from the first viewpoint.
  • FIG. 1A illustrates an example in which the pixel configuration illustrated in FIG. 3A is employed for a pixel of a display device.
  • FIG. 1B illustrates an example of a driving method of the pixel illustrated in FIG. 1A in a period T 1 (also referred to as a writing period).
  • FIG. 1C illustrates an example of a driving method of the pixel illustrated in FIG. 1A in a period T 2 (also referred to as a display period). Note that the period T 2 follows the period T 1 .
  • the pixel illustrated in FIG. 1A includes an n-channel transistor 1 whose gate is electrically connected to a terminal A and whose drain is electrically connected to a high power supply potential line; a light-emitting element 2 whose cathode is electrically connected to a low power supply potential line; a capacitor 3 one electrode of which is electrically connected to a terminal B and the other electrode of which is electrically connected to a source of the n-channel transistor 1 ; a constant current source 4 ; a switch 5 one terminal of which is electrically connected to the gate of the n-channel transistor 1 and the other terminal of which is electrically connected to the one electrode of the capacitor 3 ; a switch 6 one terminal of which is electrically connected to the source of the n-channel transistor 1 and the other terminal of which is electrically connected to an anode of the light-emitting element 2 ; and a switch 7 one terminal of which is electrically connected to the source of the n-channel transistor 1 and the other electrode of the capacitor 3 , and the other terminal of
  • a saturation region operation potential V 0 is input from the terminal A to the gate of the n-channel transistor 1 .
  • an image signal V data is input to the one electrode of the capacitor 3 from the terminal B.
  • the saturation region operation potential V 0 refers to a potential at which the n-channel transistor 1 is operated in the saturation region. In such a case, the current i 0 is generated between the drain and the source of the n-channel transistor 1 . Since the n-channel transistor 1 is operated in the saturation region, the current i 0 is expressed as follows.
  • ⁇ represents the mobility of the n-channel transistor 1
  • V gs represents the voltage between the gate and the source of the n-channel transistor 1
  • V th represents the threshold voltage of the n-channel transistor 1 .
  • k is expressed as follows.
  • W represents the channel width of the n-channel transistor 1
  • L represents the channel length of the n-channel transistor 1
  • C ox represents the gate capacitance of the n-channel transistor 1 .
  • the voltage between the gate and the source of the n-channel transistor 1 is expressed as follows.
  • V gs 2 ⁇ i 0 k ⁇ ⁇ ⁇ + V th ( 4 )
  • V C is expressed as follows.
  • V C V data - V 0 + 2 ⁇ i 0 k ⁇ ⁇ ⁇ + V th ( 5 )
  • the switches 5 and 6 are on and the switch 7 is off.
  • the terminals A and B are in a high impedance state Z. Accordingly, a node where the gate of the n-channel transistor 1 and the one electrode of the capacitor 3 are electrically connected to each other is made in a floating state, whereby the charge of the node is kept.
  • the gate capacitance of the n-channel transistor 1 is extremely lower than the storage capacitance of the capacitor 3 . Therefore, the potential of the node has substantially the same level as the potential of the one electrode of the capacitor 3 in the period T 1 . In addition, the voltage between the one electrode and the other electrode of the capacitor 3 is kept.
  • the voltage between the gate and the source of the n-channel transistor 1 has substantially the same level as the voltage V C between the one electrode and the other electrode of the capacitor 3 in the period T 1 independently of the potential of the source of the n-channel transistor 1 .
  • a current I between the drain and the source of the n-channel transistor 1 (a current supplied to the light-emitting element 2 ) is expressed as follows.
  • the current I which is supplied to the light-emitting element 2 , is independent of the potential of the source of the n-channel transistor 1 in the display device according to one embodiment of the present invention.
  • the current I is also independent of the threshold voltage of the n-channel transistor 1 in the display device according to one embodiment of the present invention.
  • Formula (8) is expressed as follows according to Taylor expansion.
  • the current supplied to the light-emitting element 2 equals the product of a formula whose value is increased and a formula whose value is reduced. Namely, in the display device according to one embodiment of the present invention, even when the mobility of the n-channel transistor 1 varies, a change in the current supplied to the light-emitting element 2 can be reduced.
  • the current I supplied to the light-emitting element 2 is independent of the potential of the source of the n-channel transistor 1 and the threshold voltage of the n-channel transistor 1 .
  • a normally-on transistor in this specification refers to a transistor whose threshold voltage has a negative value.
  • the potential of the source of the n-channel transistor 1 in the period T 1 can be expressed as V 0 +
  • the current I supplied to the light-emitting element 2 is independent of the potential of the source of the n-channel transistor 1 and the threshold voltage of the n-channel transistor 1 in the display device according to one embodiment of the present invention.
  • the above-described embodiment of the present invention can be expressed as a display device including a light-emitting element, an n-channel driving transistor, a capacitor, a constant current source, a first switch, a second switch, and a third switch.
  • one terminal of the first switch is electrically connected to a gate of the driving transistor and the other terminal of the first switch is electrically connected to one electrode of the capacitor;
  • one terminal of the second switch is electrically connected to a source of the driving transistor, and the other terminal of the second switch is electrically connected to an anode of the light-emitting element;
  • one terminal of the third switch is electrically connected to the source of the driving transistor and the other electrode of the capacitor, and the other terminal of the third switch is electrically connected to the constant current source; in a writing period, the first switch and the second switch are off, the third switch is on, the driving transistor is operated in a saturation region, an image signal is input to the one electrode of the capacitor, and a potential which has substantially the same level as a potential of
  • the pixel configuration illustrated in FIG. 3D may be employed for the pixel of the display device of one embodiment of the present invention. Specifically, even when the pixel configuration illustrated in FIG. 2 is employed, the above-described operation can be carried out.
  • the pixel illustrated in FIG. 3D may be employed for the pixel of the display device of one embodiment of the present invention. Specifically, even when the pixel configuration illustrated in FIG. 2 is employed, the above-described operation can be carried out.
  • the 2 includes a p-channel transistor 8 whose gate is electrically connected to the terminal A and whose drain is electrically connected to a low power supply potential line; a light-emitting element 9 whose anode is electrically connected to a high power supply potential line; the capacitor 3 one electrode of which is electrically connected to the terminal B and the other electrode of which is electrically connected to a source of the p-channel transistor 8 ; the constant current source 4 ; the switch 5 one terminal of which is electrically connected to the gate of the p-channel transistor 8 and the other terminal of which is electrically connected to the one electrode of the capacitor 3 ; the switch 6 one terminal of which is electrically connected to the source of the p-channel transistor 8 and the other terminal of which is electrically connected to a cathode of the light-emitting element 9 ; and the switch 7 one terminal of which is electrically connected to the source of the p-channel transistor 8 and the other electrode of the capacitor 3 , and the other terminal of which is electrically connected to the constant current source 4
  • one embodiment of the present invention can be expressed as a display device including a light-emitting element, a p-channel driving transistor, a capacitor, a constant current source, a first switch, a second switch, and a third switch.
  • one terminal of the first switch is electrically connected to a gate of the driving transistor, and the other terminal of the first switch is electrically connected to one electrode of the capacitor;
  • one terminal of the second switch is electrically connected to a source of the driving transistor, and the other terminal of the second switch is electrically connected to a cathode of the light-emitting element;
  • one terminal of the third switch is electrically connected to the source of the driving transistor and the other electrode of the capacitor, and the other terminal of the third switch is electrically connected to the constant current source; in a writing period, the first switch and the second switch are off, the third switch is on, the driving transistor is operated in a saturation region, an image signal is input to the one electrode of the capacitor, and a potential which has substantially the same level as a
  • the current supplied to the light-emitting element is independent of the potential of the source of the driving transistor in the display device according to one embodiment of the present invention. Accordingly, in the case where the source of the driving transistor and the light-emitting element are electrically connected to each other, even when the light-emitting element deteriorates over time or the environment temperature is changed, the current supplied to the light-emitting element can be kept substantially constant.
  • the current supplied to the light-emitting element is independent of the threshold voltage of the driving transistor in the display device according to one embodiment of the present invention. Accordingly, even when there are variations in threshold voltage among driving transistors which are provided in respective pixels arranged in matrix or even when the threshold voltage of the driving transistor is changed because of the deterioration, the current supplied to the light-emitting element can be kept substantially constant.
  • a change in the current supplied to the light-emitting element which is caused by an increase in the mobility of the driving transistor can be reduced in the display device according to one embodiment of the present invention. Therefore, even when there are variations in mobility among the driving transistors which are provided in respective pixels arranged in matrix, a change in the current supplied to the light-emitting element can be reduced.
  • the driving transistor is a normally-on transistor
  • the current supplied to the light-emitting element is independent of the potential of the source of the driving transistor and the threshold voltage of the driving transistor in the display device according to one embodiment of the present invention. Therefore, even in the case where the driving transistor is a normally-on transistor, the above effect can be obtained.
  • FIG. 1A illustrates a configuration example of a pixel
  • FIGS. 1B and 1C illustrate an example of a driving method of the pixel.
  • FIG. 2 illustrates a configuration example of a pixel.
  • FIGS. 3A to 3D each illustrate a configuration example of a pixel.
  • FIGS. 4A and 4B illustrate a configuration example of a display device.
  • FIG. 5A illustrates a configuration example of a pixel
  • FIG. 5B is a timing chart showing signals input to the pixel.
  • FIGS. 6A to 6F illustrate examples of electronic appliances.
  • FIGS. 4A and 4B and FIGS. 5A and 5B A configuration example of a display device according to one embodiment of the present invention will be described with reference to FIGS. 4A and 4B and FIGS. 5A and 5B .
  • FIGS. 4A and 4B illustrate a configuration example of a display device.
  • FIG. 4B illustrates part of FIG. 4A .
  • the display device illustrated in FIGS. 4A and 4B includes a pixel portion 10 including a plurality of pixels 100 arranged in matrix, a gate driver 20 which is electrically connected to the plurality of pixels 100 via respective wirings 21 and 22 which are provided in each row, a source driver 30 which is electrically connected to the plurality of pixels 100 via respective wirings 31 which is provided in each column, a constant current source 40 which is electrically connected to the plurality of pixels 100 via a wiring 41 , a constant voltage source 50 which is electrically connected to the plurality of pixels 100 via a wiring 51 , and a constant voltage source 60 which is electrically connected to the plurality of pixels 100 via a wiring 61 .
  • the constant voltage source 50 has a function of supplying a high power supply potential VDD to the wiring 51
  • the constant voltage source 60 has a function of supplying a potential V 0 which is lower than the high power supply potential VDD to the wiring 61 .
  • FIG. 5A illustrates a configuration example of the pixel 100 illustrated in FIGS. 4A and 4B .
  • the pixel 100 illustrated in FIG. 5A includes n-channel transistors 101 to 106 , a capacitor 107 , and a light-emitting element 108 .
  • a gate of the n-channel transistor 101 is electrically connected to the wiring 22 .
  • One of a source and a drain of the n-channel transistor 101 is electrically connected to the wiring 31 .
  • a gate of the n-channel transistor 102 is electrically connected to the wiring 22 .
  • One of a source and a drain of then-channel transistor 102 is electrically connected to the wiring 41 .
  • a gate of the n-channel transistor 103 is electrically connected to the wiring 21 .
  • One of a source and a drain of the n-channel transistor 103 is electrically connected to the other of the source and the drain of the n-channel transistor 101 .
  • a gate of the n-channel transistor 104 is electrically connected to the other of the source and the drain of the n-channel transistor 103 .
  • a source of the n-channel transistor 104 is electrically connected to the other of the source and the drain of the n-channel transistor 102 .
  • a drain of the n-channel transistor 104 is electrically connected to the wiring 51 .
  • a gate of the n-channel transistor 105 is electrically connected to the wiring 22 .
  • One of a source and a drain of the n-channel transistor 105 is electrically connected to the other of the source and the drain of the n-channel transistor 103 and the gate of the n-channel transistor 104 .
  • the other of the source and the drain of the n-channel transistor 105 is electrically connected to the wiring 61 .
  • a gate of the n-channel transistor 106 is electrically connected to the wiring 21 .
  • One of a source and a drain of the n-channel transistor 106 is electrically connected to the other of the source and the drain of the n-channel transistor 102 and the source of the n-channel transistor 104 .
  • One electrode of the capacitor 107 is electrically connected to the other of the source and the drain of the n-channel transistor 101 and the one of the source and the drain of the n-channel transistor 103 .
  • the other electrode of the capacitor 107 is electrically connected to the other of the source and the drain of the n-channel transistor 102 , the source of the n-channel transistor 104 , and the one of the source and the drain of the n-channel transistor 106 .
  • An anode of the light-emitting element 108 is electrically connected to the other of the source and the drain of the n-channel transistor 106 .
  • a cathode of the light-emitting element 108 is electrically connected to the low power supply potential line.
  • the n-channel transistor 104 functions as a driving transistor, and the n-channel transistors 101 , 102 , 103 , 105 , and 106 function as switches.
  • the n-channel transistor 104 corresponds to the n-channel transistor 1 in FIG. 1A
  • the n-channel transistor 103 corresponds to the switch 5 in FIG. 1A
  • the n-channel transistor 106 corresponds to the switch 6 in FIG. 1A
  • the n-channel transistor 102 corresponds to the switch 7 in FIG. 1A .
  • FIG. 5B is a timing chart showing signals which are input to the pixel illustrated in FIG. 5A . Specifically, the timing chart shows signals supplied to the wirings 21 , 22 and 31 .
  • a low-level potential is supplied to the wiring 21 . Therefore, the n-channel transistors 103 and 106 are turned off. Further, a high-level potential is supplied to the wiring 22 . Thus, the n-channel transistors 101 , 102 , and 105 are turned on. Furthermore, the image signal V data is supplied to the wiring 31 .
  • the gate of the n-channel transistor 104 is electrically connected to the wiring 61 via the n-channel transistor 105 .
  • the potential V 0 is input to the gate of the n-channel transistor 104 .
  • the potential V 0 is a potential at which the n-channel transistor 104 is operated in a saturation region.
  • the source of the n-channel transistor 104 is electrically connected to the constant current source 40 via the n-channel transistor 102 . Accordingly, a predetermined current is generated between the drain and the source of the n-channel transistor 104 .
  • the one electrode of the capacitor 107 is electrically connected to the wiring 31 via the n-channel transistor 101 . Therefore, the image signal V data is input to the one electrode of the capacitor 107 . Further, a potential which has substantially the same level as the potential of the source of the n-channel transistor 104 is input to the other electrode of the capacitor 107 . Thus, the voltage (V C ) between the pair of electrodes of the capacitor 107 becomes substantially equal to a difference between the image signal V data and the potential of the source of the n-channel transistor 104 .
  • a high-level potential is supplied to the wiring 21 . Therefore, the n-channel transistors 103 and 106 are turned on. In addition, a low-level potential is supplied to the wiring 22 . Thus, the n-channel transistors 101 , 102 , and 105 are turned off.
  • the gate of the n-channel transistor 104 is electrically connected to the one electrode of the capacitor 107 via the n-channel transistor 103 .
  • a node where the gate of the n-channel transistor 104 and the one electrode of the capacitor 107 are electrically connected to each other is made in a floating state. Accordingly, a charge existing in the node in the period t 1 is also kept in the node in the period t 2 . Further, the voltage between the pair of electrodes of the capacitor 107 in the period t 1 is kept as a voltage between the pair of electrodes of the capacitor 107 in the period t 2 .
  • the value of the gate capacitance of the n-channel transistor 104 is extremely lower than the value of the electrostatic capacitance of the capacitor 107 .
  • the voltage between the pair of electrodes of the capacitor 107 becomes equal to a voltage between the gate and the source of the n-channel transistor 104 . Accordingly, the voltage between the gate and the source of the n-channel transistor 104 in the period t 2 is independent of the potential of the source of the n-channel transistor 104 and the threshold voltage of the n-channel transistor 104 .
  • the current supplied to the light-emitting element 108 can be kept substantially constant.
  • all of the transistors provided in the pixels 100 are n-channel transistors. Therefore, the number of manufacturing steps is reduced, which enables a reduction in the manufacturing cost and an improvement in yield.
  • each of the pixels 100 can be formed with transistors in which a channel is formed in an oxide semiconductor.
  • the transistor in which the channel is formed in the oxide semiconductor can be formed through a low-temperature process which is similar to that of a transistor in which a channel is formed in amorphous silicon, and has an advantage of having higher mobility than the transistor in which the channel is formed in amorphous silicon.
  • the current supplied to the light-emitting element 108 can be kept substantially constant in the display device illustrated in FIGS. 4A and 4B and FIGS. 5A and 5B .
  • FIG. 6A illustrates a laptop computer, which includes a main body 2201 , a housing 2202 , a display portion 2203 , a keyboard 2204 , and the like.
  • FIG. 6B illustrates a personal digital assistant (PDA), which includes a main body 2211 having a display portion 2213 , an external interface 2215 , an operation button 2214 , and the like.
  • PDA personal digital assistant
  • a stylus 2212 for operation is included as an accessory.
  • FIG. 6C illustrates an e-book reader 2220 as an example of electronic paper.
  • the e-book reader 2220 includes two housings, a housing 2221 and a housing 2223 .
  • the housings 2221 and 2223 are bound with each other by an axis portion 2237 , along which the e-book reader 2220 can be opened and closed. With such a structure, the e-book reader 2220 can be used as paper books.
  • a display portion 2225 is incorporated in the housing 2221
  • a display portion 2227 is incorporated in the housing 2223 .
  • the display portion 2225 and the display portion 2227 may display one image or different images.
  • the display portions display different images from each other, for example, the right display portion (the display portion 2225 in FIG. 6C ) can display text and the left display portion (the display portion 2227 in FIG. 6C ) can display images.
  • the housing 2221 is provided with an operation portion and the like.
  • the housing 2221 is provided with a power supply 2231 , an operation key 2233 , a speaker 2235 , and the like.
  • the operation key 2233 pages can be turned.
  • a keyboard, a pointing device, or the like may also be provided on the surface of the housing, on which the display portion is provided.
  • an external connection terminal an earphone terminal, a USB terminal, a terminal that can be connected to an AC adapter or various cables such as a USB cable, or the like
  • a recording medium insertion portion, and the like may be provided on the back surface or the side surface of the housing.
  • the e-book reader 2220 may have a function of an electronic dictionary.
  • the e-book reader 2220 may be configured to transmit and receive data wirelessly. Through wireless communication, desired book data or the like can be purchased and downloaded from an electronic book server.
  • electronic paper can be applied to devices in a variety of fields as long as they display information.
  • electronic paper can be used for posters, advertisement in vehicles such as trains, display in a variety of cards such as credit cards, and the like in addition to e-book readers.
  • FIG. 6D illustrates a mobile phone.
  • the mobile phone includes two housings, housings 2240 and 2241 .
  • the housing 2241 is provided with a display panel 2242 , a speaker 2243 , a microphone 2244 , a pointing device 2246 , a camera lens 2247 , an external connection terminal 2248 , and the like.
  • the housing 2240 is provided with a solar cell 2249 charging of the mobile phone, an external memory slot 2250 , and the like.
  • An antenna is incorporated in the housing 2241 .
  • the display panel 2242 has a touch panel function.
  • a plurality of operation keys 2245 which are displayed as images is illustrated by dashed lines in FIG. 6D .
  • the mobile phone includes a booster circuit for increasing a voltage output from the solar cell 2249 to a voltage needed for each circuit.
  • the mobile phone can include a contactless IC chip, a small recording device, or the like in addition to the above structure.
  • the display orientation of the display panel 2242 changes as appropriate in accordance with the application mode.
  • the camera lens 2247 is provided on the same surface as the display panel 2242 , and thus it can be used as a video phone.
  • the speaker 2243 and the microphone 2244 can be used for videophone calls, recording, and playing sound, etc. as well as voice calls.
  • the housings 2240 and 2241 in a state where they are developed as illustrated in FIG. 6D can be slid so that one is lapped over the other; therefore, the size of the mobile phone can be reduced, which makes the mobile phone suitable for being carried.
  • the external connection terminal 2248 can be connected to an AC adapter or a variety of cables such as a USB cable, which enables charging of the mobile phone and data communication. Moreover, a larger amount of data can be saved and moved by inserting a recording medium to the external memory slot 2250 . Further, in addition to the above functions, an infrared communication function, a television reception function, or the like may be provided.
  • FIG. 6E illustrates a digital camera.
  • the digital camera includes a main body 2261 , a display portion (A) 2267 , an eyepiece 2263 , an operation switch 2264 , a display portion (B) 2265 , a battery 2266 , and the like.
  • FIG. 6F illustrates a television set.
  • a display portion 2273 is incorporated in a housing 2271 .
  • the display portion 2273 can display images.
  • the housing 2271 is supported by a stand 2275 .
  • the television set 2270 can be operated by an operation switch of the housing 2271 or a separate remote controller 2280 .
  • Channels and volume can be controlled with an operation key 2279 of the remote controller 2280 so that an image displayed on the display portion 2273 can be controlled.
  • the remote controller 2280 may have a display portion 2277 in which the information outgoing from the remote controller 2280 is displayed.
  • the television set 2270 is preferably provided with a receiver, a modem, and the like.
  • a general television broadcast can be received with the receiver.
  • the television set is connected to a communication network with or without wires via the modem, one-way (from a sender to a receiver) or two-way (between a sender and a receiver or between receivers) data communication can be performed.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Manufacturing & Machinery (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Control Of El Displays (AREA)
  • Electroluminescent Light Sources (AREA)
US13/560,133 2011-08-05 2012-07-27 Display device Expired - Fee Related US8836689B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2011-172236 2011-08-05
JP2011172236 2011-08-05

Publications (2)

Publication Number Publication Date
US20130033475A1 US20130033475A1 (en) 2013-02-07
US8836689B2 true US8836689B2 (en) 2014-09-16

Family

ID=47626670

Family Applications (1)

Application Number Title Priority Date Filing Date
US13/560,133 Expired - Fee Related US8836689B2 (en) 2011-08-05 2012-07-27 Display device

Country Status (3)

Country Link
US (1) US8836689B2 (enExample)
JP (1) JP6023494B2 (enExample)
KR (1) KR101960971B1 (enExample)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US12089459B2 (en) 2019-05-10 2024-09-10 Semiconductor Energy Laboratory Co., Ltd. Display apparatus and electronic device

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013251255A (ja) 2012-05-04 2013-12-12 Semiconductor Energy Lab Co Ltd 発光装置の作製方法
US9269315B2 (en) 2013-03-08 2016-02-23 Semiconductor Energy Laboratory Co., Ltd. Driving method of semiconductor device
TWI696108B (zh) 2015-02-13 2020-06-11 日商半導體能源研究所股份有限公司 功能面板、功能模組、發光模組、顯示模組、位置資料輸入模組、發光裝置、照明設備、顯示裝置、資料處理裝置、功能面板的製造方法
GB2618029A (en) * 2021-09-30 2023-10-25 Boe Technology Group Co Ltd Pixel driving circuit, display panel, method of driving display panel
TW202416249A (zh) * 2022-10-07 2024-04-16 群創光電股份有限公司 調變裝置

Citations (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5550066A (en) 1994-12-14 1996-08-27 Eastman Kodak Company Method of fabricating a TFT-EL pixel
US5684365A (en) 1994-12-14 1997-11-04 Eastman Kodak Company TFT-el display panel using organic electroluminescent media
US20030117352A1 (en) * 2001-10-24 2003-06-26 Hajime Kimura Semiconductor device and driving method thereof
US6661180B2 (en) * 2001-03-22 2003-12-09 Semiconductor Energy Laboratory Co., Ltd. Light emitting device, driving method for the same and electronic apparatus
US20040196239A1 (en) * 2003-04-01 2004-10-07 Oh-Kyong Kwon Light emitting display, display panel, and driving method thereof
US20050057459A1 (en) * 2003-08-29 2005-03-17 Seiko Epson Corporation Electro-optical device, method of driving the same, and electronic apparatus
US6958750B2 (en) 2001-07-16 2005-10-25 Semiconductor Energy Laboratory Co., Ltd. Light emitting device
US7046240B2 (en) * 2001-08-29 2006-05-16 Semiconductor Energy Laboratory Co., Ltd. Light emitting device, method of driving a light emitting device, element substrate, and electronic equipment
US20060103322A1 (en) * 2004-11-17 2006-05-18 Lg.Philips Lcd Co., Ltd. Apparatus and method for driving organic light-emitting diode
US20070064469A1 (en) * 2005-09-16 2007-03-22 Semiconductor Energy Laboratory Co., Ltd. Display device and driving method of the same
US20070063993A1 (en) * 2005-09-16 2007-03-22 Semiconductor Energy Laboratory Co., Ltd. Display device and driving method of display device
US20070126664A1 (en) * 2005-12-02 2007-06-07 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device, display device, and electronic device
US20090051628A1 (en) * 2007-08-23 2009-02-26 Oh-Kyong Kwon Organic light emitting display and driving method thereof
US7859491B2 (en) * 2006-05-18 2010-12-28 Lg Display Co., Ltd. Pixel circuit of organic light emitting display
US8054250B2 (en) * 2006-08-08 2011-11-08 Samsung Mobile Display Co., Ltd Pixel, organic light emitting display, and driving method thereof
US20120026145A1 (en) * 2010-08-02 2012-02-02 Samsung Mobile Display Co., Ltd. Pixel and Organic Light Emitting Display Device Using the Same
US8164547B2 (en) * 2006-04-05 2012-04-24 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device, display device, and electronic device
US8519392B2 (en) * 2001-09-21 2013-08-27 Semiconductor Energy Laboratory Co., Ltd. Light emitting device, driving method of light emitting device and electronic device

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TW526455B (en) * 1999-07-14 2003-04-01 Sony Corp Current drive circuit and display comprising the same, pixel circuit, and drive method
JP4049018B2 (ja) * 2003-05-19 2008-02-20 ソニー株式会社 画素回路、表示装置、および画素回路の駆動方法
US8426866B2 (en) * 2004-11-30 2013-04-23 Semiconductor Energy Laboratory Co., Ltd. Display device and driving method thereof, semiconductor device, and electronic apparatus
KR101194861B1 (ko) * 2006-06-01 2012-10-26 엘지디스플레이 주식회사 유기발광다이오드 표시소자
KR100811332B1 (ko) * 2006-06-19 2008-03-07 비오이 하이디스 테크놀로지 주식회사 유기 전계 발광 표시 장치
CA2660598A1 (en) * 2008-04-18 2009-06-22 Ignis Innovation Inc. System and driving method for light emitting device display

Patent Citations (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08241047A (ja) 1994-12-14 1996-09-17 Eastman Kodak Co Ｔｆｔ−ｅｌ画素製造方法
US5684365A (en) 1994-12-14 1997-11-04 Eastman Kodak Company TFT-el display panel using organic electroluminescent media
US5550066A (en) 1994-12-14 1996-08-27 Eastman Kodak Company Method of fabricating a TFT-EL pixel
US6661180B2 (en) * 2001-03-22 2003-12-09 Semiconductor Energy Laboratory Co., Ltd. Light emitting device, driving method for the same and electronic apparatus
US7649516B2 (en) 2001-07-16 2010-01-19 Semiconductor Energy Laboratory Co., Ltd. Light emitting device
US6958750B2 (en) 2001-07-16 2005-10-25 Semiconductor Energy Laboratory Co., Ltd. Light emitting device
US7046240B2 (en) * 2001-08-29 2006-05-16 Semiconductor Energy Laboratory Co., Ltd. Light emitting device, method of driving a light emitting device, element substrate, and electronic equipment
US20090021539A1 (en) * 2001-08-29 2009-01-22 Semiconductor Energy Laboratory Co., Ltd. Light Emitting Device, Method of Driving a Light Emitting Device, Element Substrate, and Electronic Equipment
US8519392B2 (en) * 2001-09-21 2013-08-27 Semiconductor Energy Laboratory Co., Ltd. Light emitting device, driving method of light emitting device and electronic device
US20030117352A1 (en) * 2001-10-24 2003-06-26 Hajime Kimura Semiconductor device and driving method thereof
US20050206593A1 (en) * 2003-04-01 2005-09-22 Samsung Sdi Co., Ltd. Light emitting display, display panel, and driving method thereof
US20040196239A1 (en) * 2003-04-01 2004-10-07 Oh-Kyong Kwon Light emitting display, display panel, and driving method thereof
US20050057459A1 (en) * 2003-08-29 2005-03-17 Seiko Epson Corporation Electro-optical device, method of driving the same, and electronic apparatus
US20060103322A1 (en) * 2004-11-17 2006-05-18 Lg.Philips Lcd Co., Ltd. Apparatus and method for driving organic light-emitting diode
US20070063993A1 (en) * 2005-09-16 2007-03-22 Semiconductor Energy Laboratory Co., Ltd. Display device and driving method of display device
US20070064469A1 (en) * 2005-09-16 2007-03-22 Semiconductor Energy Laboratory Co., Ltd. Display device and driving method of the same
US20070126664A1 (en) * 2005-12-02 2007-06-07 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device, display device, and electronic device
US8164547B2 (en) * 2006-04-05 2012-04-24 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device, display device, and electronic device
US7859491B2 (en) * 2006-05-18 2010-12-28 Lg Display Co., Ltd. Pixel circuit of organic light emitting display
US8054250B2 (en) * 2006-08-08 2011-11-08 Samsung Mobile Display Co., Ltd Pixel, organic light emitting display, and driving method thereof
US20090051628A1 (en) * 2007-08-23 2009-02-26 Oh-Kyong Kwon Organic light emitting display and driving method thereof
US20120026145A1 (en) * 2010-08-02 2012-02-02 Samsung Mobile Display Co., Ltd. Pixel and Organic Light Emitting Display Device Using the Same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US12089459B2 (en) 2019-05-10 2024-09-10 Semiconductor Energy Laboratory Co., Ltd. Display apparatus and electronic device

Also Published As

Publication number Publication date
US20130033475A1 (en) 2013-02-07
JP2013054345A (ja) 2013-03-21
KR20130016063A (ko) 2013-02-14
JP6023494B2 (ja) 2016-11-09
KR101960971B1 (ko) 2019-03-21

Similar Documents

Publication Publication Date Title
US6750833B2 (en) System and methods for providing a driving circuit for active matrix type displays
US8836689B2 (en) Display device
US8847933B2 (en) Display device
JP5300498B2 (ja) 表示装置
CN102884477B (zh) 液晶显示设备及其驱动方法
TWI541786B (zh) 顯示裝置
US10714010B2 (en) Pixel compensation circuit, method for driving the same, organic light-emitting diode display panel, and display device
US20250241128A1 (en) Display panel and display device
US9218761B2 (en) Method of driving display device, display device, and electronic appliance
CN111179827A (zh) 外部补偿goa电路及显示面板
CN114067737B (zh) 显示面板及显示装置
CN118038788A (zh) 一种显示面板和显示装置

Legal Events

Date Code Title Description
AS Assignment

Owner name: SEMICONDUCTOR ENERGY LABORATORY CO., LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MIYAKE, HIROYUKI;REEL/FRAME:028658/0296

Effective date: 20120717

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

STCF Information on status: patent grant

Free format text: PATENTED CASE

MAFP Maintenance fee payment

Free format text: PAYMENT OF MAINTENANCE FEE, 4TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1551)

Year of fee payment: 4

FEPP Fee payment procedure

Free format text: MAINTENANCE FEE REMINDER MAILED (ORIGINAL EVENT CODE: REM.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

LAPS Lapse for failure to pay maintenance fees

Free format text: PATENT EXPIRED FOR FAILURE TO PAY MAINTENANCE FEES (ORIGINAL EVENT CODE: EXP.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362

FP Lapsed due to failure to pay maintenance fee

Effective date: 20220916